AB1293 OMICRON BREAKTHROUGH INFECTIONS AMONG RITUXIMAB AND NON-RITUXIMAB TREATED PATIENTS WITH AUTOIMMUNE INFLAMMATORY RHEUMATIC DISEASES: A MULTICENTER CONTROLLED STUDY
Authors: V. Furer, T. Eviatar, D. Zisman, H. Peleg, D. Paran, D. Levartovsky, I. Kaufman, A. Broyde, A. Polachek, J. Feld, A. Haddad, T. Gazitt, M. Elias, N. Hijaze, Y. Friedlander, O. Elkayam
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Little is known about the efficacy of booster COVID-19 vaccination in rituximab (RTX)-treated patients with autoimmune inflammatory rheumatic diseases (AIIRD). <h3>Objectives</h3> To estimate COVID-19 breakthrough infection rate in AIIRD patients treated with RTX compared to patients treated with other therapies and immunocompetent controls. <h3>Methods</h3> This observational multi-center study investigated COVID-19 infection rate and humoral response (anti-S1/S2 IgG) to the BNT162b2 mRNA vaccination in RTX-treated vs non-RTX treated AIIRD patients and immunocompetent controls for 18 months. To investigate the impact of the 3rd and 4th mRNA COVID-19 vaccine doses, a survival analysis was applied. Predictors of time-to-infection were analyzed using a multivariate Cox proportional hazard model. <h3>Results</h3> A total of 115 RTX-treated patients, 590 non-RTX-treated patients, and 121 immunocompetent controls were included in the analysis. AIIRD patients received more vaccine doses than controls, median 3 (range 2-4) vs 2 (2-4), respectively, p&lt;0.0001; the rate of vaccination with the 3rd and 4th vaccine doses were 53.82% (n=402) vs 32.8% (n=41), and 3.88% (n=29) vs 2.4% (n=3), respectively, p &lt;0.0001 for both comparisons. Patients treated with RTX within one year from the last vaccination (n=84) had the lowest anti-S1/S2 IgG level following each vaccination compared to others patients and controls. RTX-treated patients had the highest rate of COVID-19 infection since the start of the vaccination campaign compared to the AIIRD patients in general and controls, 32.26% (40/124), 27.29% (170/623), and 28.8% (36/125), respectively, p=0.2206. During the Omicron surge, time-to infection from the last booster vaccination was shorter among AIIRD patients compared to controls, irrespective of the type of anti-rheumatic therapies (Figure 1A). In a Cox-regression model, a time interval between the RTX treatment and the last vaccination was associated with a lower risk to contract COVID-19, HR 0.998 (95% CI 0.997-1), p=0.0298 (Figure 1B) For each 30-day interval between the RTX treatment and the vaccination date, the risk to contract COVID-19 declined 0.941-fold. The risk to contract COVID-19 among RTX-treated patients within the last year after adjustment to age and S1/S2 serology was HR 2.077, 95% CI 1.056-4.086, p=0.0342. Reassuringly, no cases of severe COVID-19 or COVID-19-related mortality were reported during the Omicron surge. <h3>Conclusion</h3> This study found comparable rates of the Omicron infection rate among vaccinated AIIRD patients treated with RTX and other immunomodulators. Recent exposure to RTX predisposed to a breakthrough COVID-19 infection. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.